This note is in response to the National Park Service news release dated Sept. 14, 2015, about subjecting electronic cigarettes to the same rules imposed on combustible tobacco products.
There is no need for such restrictions on the use of e-cigarettes and no public health or environmental benefit from doing so.
E-cigarettes involve no combustion. There is no fire hazard.
As noted in your press release, exhaled vapor contains far less nicotine than secondhand cigarette smoke. While exhaled cigarette smoke is extremely hazardous, almost none of this risk is attributable to the nicotine. The amounts of nicotine in exhaled vapor are comparable to the amounts of nicotine people ingest on a daily basis. Eggplant, tomatoes, potatoes, peppers and other common foods contain trace quantities of nicotine. I am not aware of any public-health authority ever urging restriction of intake of these vegetables or other nicotine-containing foods by infants, pregnant women or others to avoid brain damage, lung damage or addiction.
Exhaled e-cigarette vapor does contain minute trace quantities of a variety of other toxic chemicals. Nonsmokers also exhale trace quantities of some of these same toxic chemicals. The amounts exhaled are so small that they are barely measurable above background in most indoor environments. They are surely far less than the amounts of these same chemicals released by wood fires.
The references noted below include links to papers in support of the statements made above. The first also includes a description of my background and how both I and R Street became involved in the e-cigarette issue.1-3
- J.L. Nitzkin, “E-cigarettes: A life-saving technology or a way for tobacco companies to re-normalize smoking in American society?,” FDLI’s Food and Drug Policy Forum. 2014;4(6) (June 30):1-17. http://www.rstreet.org/wp-content/uploads/2014/07/20140630FDLI-EcigForum.pdf 
- K. Farsalinos and R. Polosa, “Safety evaluation and risk assessment of electronic cigarettes as tobacco cigarette substitutes: A systematic review,” Therapeutic Advances in Drug Safety. 2014;5(20):67-86. http://www.ncbi.nlm.nih.gov/pubmed/25083263 
- A. McNeill , L. Brose, R. Calder and S. Hitchman, “E-cigarettes: An evidence update,” a report commissioned by Public Health England, London, England. August 2015.; “An Evidence Update Plus Policy Implications,” Public Health England, Aug. 19 2015. https://www.gov.uk/government/publications/e-cigarettes-an-evidence-update 
Please let me know if you or any of your colleagues would like additional information on this topic. I would welcome the opportunity to provide additional references and to discuss this with whoever advised NPS to institute this policy.
- “http://www.rstreet.org/wp-content/uploads/2014/07/20140630FDLI-EcigForum.pdf”: http://www.rstreet.org/wp-content/uploads/2014/07/20140630FDLI-EcigForum.pdf
- “http://www.ncbi.nlm.nih.gov/pubmed/25083263”: http://www.ncbi.nlm.nih.gov/pubmed/25083263
- “https://www.gov.uk/government/publications/e-cigarettes-an-evidence-update”: https://www.gov.uk/government/publications/e-cigarettes-an-evidence-update